Yeah it's 1.425/2.086v, and the XT/XTX use the same voltages. You have 1.475 there for default - It wont hurt, but it's not needed. The 2.089v is just a slight variation, no matter as it's only 3 thousandths of a volt lol.

well my overclocking is finally working im now at core 702 mem 801 im at 10998 in 3dmark05 test. I think someone might want to tell or repost how to set the default 3d memory voltage and core voltage because I think most people aren't setting these clocks and cannot get a stable overclock setting with ati tools because of this. I know because I felt like a moron tell I finally found my mistake, in a overclocking guide, in small print only listed once

It explains all about the 2D/3D modes of the X1900 series, and a lot can be applied to the X1800 series. The guide is a bit out of date now, but there is still a ton of useful tips in there. Perhaps I'll make an up-to-date version and post it in the articles.